Engraver&#39;s mat



A ril 18, 1933. A. B. GLENN 1 ENGRAVER S MAT Filed Dec. 7, 1927 Patented Apr. 18, 1933 UNITED "STATES ARTHUR IBQGLENN, or os ANGELES, CALIFORNIA;

Gum's mam 7 Application filed December 7, 1927. Serial No. 288,410.

This invention relates generally toprinting and more particularly to stereotyping.

According to methods now generally in use, in preparing a stereotype, it is necessary for the artist to prepare a drawing on paper. Usually a photograph must be made from this drawing, and an engraving 'or a matrix is formed thereafter fromwhich the stereotype is produced. 1 1 10 It has been attempted heretofore, to. prepare a matrix for stereotyping by having the artistrdraw directly upon a metal plate having a. facing consisting of a'layerof chalk. According to this method the artist etched the facing with a sharp stylus, therebyproducing a matrix which could be usedin producing a stereotype. In etching uponthis' mat the point of the stylus ofcourse, in formn in a line, penetrated through the entire to depth of the facing, downto the backing sheet of metal. When in the mold the type metal flowed into these engraved lines and the face of the 'metal plate backing sheet determined the position of the printing faces of the stereotype corresponding to the engraved lines. This method has been found unsatisfactory for the reason that the metal plate is a conductor of heat and chills rapidly leaving an inefiicient and chilled face on the stereotype and also because the cha-lk'and compositions heretofore used to form the facing of the mat have been found to be. brittle. Due to the fact that. a metal plate makes -apoor backing sheet, chilling rapidly, and to the brittleness of the chalk it is impossible for i the artist to produce a clean, unbroken line. Heretofore no material has been discovered suitable for making the facing of such a mat. Such a facing must be soft enough to permit the artist to draw upon it readily without cracking off on the edges of the lines formed by thestylus, and furthermore, the facing must be' sufliciently elastic to prevent from forming cracks when handled, shipped, or 5 when kept in stock for indefinite periods. The material forming the facing must also resist the temperature and weight of the type metal when flowed over it in the mold.

The general object of this invention is-to provide a mat which becomes the matrix,

thereby eliminating steps now necessary in the usual methods of producing stereotypes. One of the objects of the invention is to produce an efiicient mat upon Which the artist may draw or'etch directly'to produce a matriX, and to provide the said mat with char-' acteristics which will enable it'to be used directly in a stereotype mold; also to avoid the use of metal in the said mat.

It is sometimes desiredto send engrave ings-to' distant points through the mail or by'expre ss. The matrix prepared according to my invention can be readily sent through the mails without danger of injury and it is one of the objects of the inventionto produce a mat which will meet this-requirement.

Further objects of the invention will appear hereinafter. r

' The invention consists in the novel mat to be describedv hereinafter and in the novel characteristics which cooperate to produce an'elficient mat suitable for forming a ma trix.

A preferred embodiment of the invention is described in the following specification, and the broad scope of the invention is pointed out in the appended claims.

. In the drawing: Figure 1 is a side elevation illustrating the first step in the production'of the mat;

' Figure 2 is a side elevation illustrating the mat at a further stage in its manufacture; this view particularly illustrates the finish ing of the mat to the desired thickness; 1 1 Figure 3 is a cross-section through the completed mat; V V

Figure 4c isa vertical section through a molding box and illustrating the manner'in which the matrix is employed in forming the stereotype; and

Figure -5 is an illustration showing, as an example, acharacter of print that can, be produced from a stereotype manufactured in accordance with my invention. a

In practicing the invention, I prefer to employ a-backing sheet which is in the form of a dense, pressed paper board. A suitable board for this purpose'is sold in the market under the name of Vehisote. The backing mo sheet must have certain properties which are important as affecting the character of the printing face of the stereotype. In this connection, it should be understood that in drawing upon the mat the artist scratches or etches completely through the facing on a backing sheet and for this purpose uses a sharp stylus of steel or similar material. The face of the backing sheet should be such that the point of the stylus will not raise any fibres from the face of the backing sheet or scratch the face of the backing sheet. In other words, the face of the backing sheet which carries the facing of my composition should be hard and resistant to the action of the stylus. I do not use a metal backing sheetfor the reason that casting metal directly against metal has a tendency to chill the stereotyping metal and mars the printing face of the stereotype formed; also such a backing sheet tends to expand from the heat in the mold and produces buckling or bulges in the matrix which interfere with the production of perfect stereotypes. I have found that the paper backing sheet described, effectively carries the facing and at the same time resists the temperature of the type metal when flowed onto it in the mold, maintaining the heat of the metal and producing perfect reproductions.

In the drawing, 1 indicates a backing sheet of paper board of the character suggested above. In preparing this backing sheet, I prefer to dress it down to a thickness of about after which I coat the faces of the sheet with shellac, using, however, just sufiicient shellac to be absorbed by the surface of the board. The effect of the shellac is to produce asmooth waterproof face on the board and admirably adapts it to produce a clean printing face for the stereotype.

The composition which I prefer to use to form the facing for the mat is a mineral earth and preferably is composed substantially or principally of magnesium-silicate. For this purpose, I prefer to employ purified talcum powder. In preparing the composition, I mix together certain ingredients including substantially one part of ground glue by measure to eight parts of water by measure. To this I add about two ounces of yellow Diamond Dye for each gallon of the glue and water. The Diamond Dye is included not primarily as a coloring but to give a smoother texture to the composition. In order to increase the preserving qualities, I prefer to add a few drops of crude carbolic acid. I mix the above ingredients with a quantity of the base or purified talcum powder in such quantities as to form a batter-like mixture of approximately the consistency of soft mud or heavy pancake batter. In other words, I form a thin mush or thick paste from these ingredients. On the upper face of the backing sheet 1, I heap a mass 2 of this paste (see Figure 1). This should be done to a considerable depth, preferably about for a reason which will appear hereinafter. While the paste is still moist, I wipe OK the edge portions 3 to a point indicated by the dotted lines in Figure 1. This leaves a margin on the backing sheet uncovered by the paste.

I find that in applying the paste to the backing sheet, it is necessary to take steps to insure that the composition in the vicinity of the face of the backing sheet will be dense, that is to say that the particles of the composition at this point will be tightly packed together. This is necessary in order to insure a continuous and unpitted face in the finished mat. For this reason, I prefer to jog the unfinished mat while the moist paste is resting upon it. This jogging settles the mass 2 and insures the desired density in the lower strata of the composition.

The backing sheet with the paste 2 upon it is then dried in an oven. The temperature in the oven should not exceed about 250 F., and should not be sufficient to bake the paste. The function of the oven is merely to dry the paste and no boiling or baking of the paste should take place. The drying should be effected quickly. However, it is not essential that the drying be effected in an oven, and if desired, the mass can be dried in the air or in the sun providing the temperature is not permitted to rise too high.

When the paste has become thoroughly dry, it will be found that a portion of the liquid in the composition has risen to the upper layers of the paste, forming a thin, hard coating, but this liquid which operates as a binder operates effectively to cause the dried paste to adhere firmly to the face of the board; below this thin, hard coating the composition will be found to be soft and pliable yet with its particles firmly bound together.

It is then necessary to remove the upper portion of the dried mass. This is accomplished by running the mat through a sander or preferably through a planer having a planer tool 4 with a plurality of knives 5 such as illustrated in Figure 2. In this operation, I prefer to dress the hardened paste 6 so as to leave a facing 7 on the backing board of approximately in thickness. This thickness, however, may be varied as desired to suit the special requirements of the trade. The planer or sander leaves a smooth, uninterrupted face 8. If the mat is prepared as described above, this face will be found to be devoid of pits or inequalities in its face.

The finished mat illustrated in Figure 3 is then ready to be drawn upon or etched by the artist who uses for this purpose a stylus, hard pencil or other sharp instrument. In making the drawing, however, the artist should take care that the point of the stylus in making any line of the drawing penetrates a casting box 10 with the engraved facing 7 of the matrix uppermost. The mold having been closed and clamped up, its interior may be filled with a type metal composition to produce a stereotype 11. In this view the en aved lines 12 indicate how the engraving is rought down to the face of the backing sheet so as to insure a stereotype thatwill print perfectly. While the mat is particularly adapted for making line drawings, it is evident that by scraping away small areas of the facing of the matrix, solid black areas in the print that can be produced. A good example of the character of a print that can be formed by this method is illustrated in Figure 5.

The glue in my composition of course operates as a binder and also causes the composition to adhere to the backing sheet.

The relatively great depth of the paste assists in increasing thedensity of the composition at the level of the face 8.

This mat embodying my invention need not be handled with great care, that is to say, the facing 7 is relatively tough and resilient, and in fact the mat can be bent considerably without injury to thefacing. The facing has suflicient resiliency to permit this.

glue by measure to eight parts of water by .measure, to which has been added substantially two ounces of yellow Diamond Dye to each gallon of the mixture. r

3. As a new article of manufacture, an engravers mat consisting of a backing sheet having a water-proof coating and having a facing on the sheet consisting of a composition of talcum powder mixed with a binder.

Signed at Los Angeles, California, this 26 day of November, 1927.

ARTHUR B. GLENN.

While the matrix described herein maybe I used for producing stereotypes, it also may be used in the bottom of a small mold for molding rubber to produce a rubber stamp.

One of the principal advantages of the use of my invention arises from the fact that I avoid the use of a metallic backing sheet and employ a backing sheet of a material having no chilling. effect upon the type material when it is run into the mold. This enables fine and accurate reproductions to be produced from the matrix.

The method disclosed in this application will form the subject matter of another application for patent.

What I claim is 1. As a new article of manufacture, an engravers mat capable of being engraved upon, consisting of a backing sheet of paperboard with a coating of shellac, and a facin adhering to the board on the shellacked face and consistingsubstantially of a composition of magnesium-silicate.

2. As a new article of manufacture, an artists mat consisting of a backing sheet of pressed paper-board with a water-proof coating, and a facing on the water-proof coated sheet consisting of a dried composition of the following ingredients: talcum powder mixed with substantially one part of ground 

